1. Field of the Invention
This invention relates to a new electrically operated control device and system for an appliance as well as to new methods of making the same.
2. Prior Art Statement
It is known to provide a control device for a control system for an appliance wherein the system comprises a power source of alternating electrical current that has a repeating voltage wave cycle and a repeating current wave cycle and load means for using the electrical current to provide an output of the load means for the appliance, the control device comprising relay means having normally open contact means and coil means for closing the contact means only when the coil means is energized, and electrical circuit means for interconnecting the power source to the load means only through the contact means to provide the output and only when the contact means are closed by the coil means, the control device comprising control means for causing the coil means to close the contact means substantially at a certain point on the voltage wave cycle each time the relay coil means closes the contact means from the open condition thereof whereby the current flow through the contact means at each closing thereof is at substantially a desired level thereof, the control means having means to begin to energize the coil means with the power source at substantially a desired lead point on the voltage wave cycle thereof so as to tend to cause the contact means to subsequently close substantially at the certain point on the voltage wave cycle each time the load means is to be interconnected to the power source whereby a lag time period exists between the desired lead point and the certain point, the control means having sensing means to sense the lag time by detecting when the coil current of the relay coil means decreases momentarily by the contact means initially closing during that particular cycle of operation of the control device, the control means having means to automatically adjust the desired lead point should the sensed lag time on a certain previous cycle of operation not cause the contact means to close substantially at the certain point in order to tend to cause the contact means to close substantially at the certain point during future cycles of operation. For example, see the Fowler U.S. Pat. No. 4,745,515.
While the illustrated embodiment of the Fowler U.S. Pat. No. 4,745,515, illustrates a parallel relay contact arrangement for detecting the relay pull in time, such patent describes an alternate means as being a transistor circuit that monitors the coil current to determine when the relay armature completes its magnetic circuit because in a typical relay operation the coil current decreases momentarily when the magnetic circuit of the armature is mechanically completed.
For example, such patent states in column 12, lines 11-22, the following:
"There are alternate means of detecting relay pull in time vs. the parallel relay contact arrangement as previously described. For example, one means is a transistor circuit that monitors the coil current to determine when the relay armature completes its magnetic circuit because in a typical relay operation, the coil current decreases momentarily when the magnetic circuit of the armature is mechanically completed. This decreasing of coil current can be detected by a peak sample and hold circuit that will approximate the pull in of the armature and corresponding linkages that operate the relay contact."
However, no transistor circuit is disclosed or described in the Fowler U.S. Pat. No. 4,745,515, for so detecting the momentary decrease in coil current.